It is known in the art to use a specific particle as one of polymerization catalyst components to produce a particulate polymer having a uniform particle shape, in order to inhibit adherence of the particulate polymer in production to a polymerization reactor. Such adherence, which is called “fouling” in the art, tends to occur when producing a particulate polymer by polymerizing an addition-polymerizable monomer such as an olefin by a slurry, gas-phase or bulk polymerization method, with the use of a polymerization catalyst formed from a combination of a transition metal catalyst component (for example, a metallocene complex and a non-metallocene compound) with an organometallic catalyst component such as aluminoxane. Such fouling is particularly tremendous in pre-polymerization of an olefin with the use of such a polymerization catalyst.
For example, JP 2003-171413A discloses a pre-polymerization method of an olefin, comprising steps of (i) modifying silica gel particles with the combined use of an organozinc compound, trifluorophenol and water, thereby obtaining modified silica gel particles, and (ii) pre-polymerizing an olefin in the presence of a primary polymerization catalyst formed by the combined use of the above modified silica gel particles, a transition metal compound and an organoaluminum compound.
Also, JP 2006-233115A discloses a production method of a pre-polymerized catalyst component for addition polymerization, comprising steps of (i) contacting a transition metal compound with modified particles, thereby obtaining a primary polymerization catalyst, and (ii) pre-polymerizing an olefin in the presence of the above primary polymerization catalyst; a production method of a pre-polymerized catalyst for addition polymerization; and a production method of an addition polymer with the use of the above pre-polymerized catalyst, wherein the transition metal compound in above step (i) is used in a powdery state, or in a slurry state.